Is there a way to make a node property value the default?
I'll post another answer since this one will actually solve your problem (I hope). Use this script to set the interpolation of each and every one of your &quot;Image Texture&quot; nodes to &quot;Closest&quot; :
import bpy

for mat in bpy.data.materials:
    if not mat.node_tree:
        continue
    for node in mat.node_tree.nodes:
        if node.type == 'TEX_IMAGE':
            node.interpolation = 'Closest'


How to run a script